The Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) Release 8 and 9 discontinuous reception (DRX) procedures determine the period of physical downlink control channel (PDCCH) reception. PDCCH reception and the configured semi-persistent scheduling determine when a physical downlink shared channel (PDSCH) on a downlink (DL) component carrier (CC) and a physical uplink shared channel (PUSCH) transmission on an uplink (UL) CC may occur.
In LTE Release 8/9 (also applicable to LTE Release 10), the network may configure a WTRU with parameters for discontinuous reception (DRX). DRX is a functionality that allows a WTRU to not monitor or decode the PDCCH, for the purpose of lowering WTRU power consumption. The DRX functionality relies on a specific set of rules based on PDCCH activity for a number of specific RNTIs. These rules ensure that the network and the WTRU are properly synchronized with respect to when the WTRU can be reached using the control signaling.
LTE-Advanced (LTE Release 10) is an evolution that aims to improve LTE Release 8/9's data rates using, among other methods, bandwidth extensions also referred to as carrier aggregation (CA). With CA, the WTRU may transmit and receive simultaneously over the PUSCH and the PDSCH (respectively) of multiple Component Carriers (CCs). Up to five CCs in the UL and in the DL may be used, thus supporting flexible bandwidth assignments up to 100 MHz.